It exist systems for preparing beverages such as coffee by forcing a liquid through ingredients contained in the capsule using centrifugal forces.
WO 2008/148604 for example relates to a capsule for preparing a beverage or liquid food from a substance, in a centrifugal brewing unit, by passing water through the substance contained in the capsule by using brewing centrifugal forces comprising: an enclosure containing a predetermined dose of substance; opening means which opens under the centrifugal effect to allow the brewed liquid to leave the capsule. The capsule may also comprise means for engaging the capsule to external rotational driving means of a centrifugal brewing device wherein the engaging means are configured to offer a resistance to torque during rotation of the capsule for maintaining the capsule in a reference rotational position.
Thereby, the effect of centrifugal forces to brew coffee or prepare other food substances presents many advantages compared to the normal brewing methods using pressure pumps. For example, in traditional espresso or lungo coffee type brewing methods using a pressure pump, it is very difficult to master all the parameters which influence the quality of extraction of delivered coffee extract. These parameters are typically the pressure, the flow rate which decreases with the pressure, the compaction of the coffee powder which also influences the flow characteristics and which depends on the coffee ground particle size, the temperature, the water flow distribution and so on. In particular, it is not easy to vary the extraction pressure and flow rates because there are essentially determined by the static pressure deliverable by the pump, the resistance of the bed of coffee and the downstream filtering system.
For a centrifugal extraction, the rotating capsule is used as a centrifugal pump. The rotational speed thus determines the flow rate of the centrifuged liquid coming out of the capsule. The quality of the beverage to be prepared depends on the control, in particular, of the flow rate. In particular, the flow rate is influenced by two parameters: the rotational speed of the capsule in the device and the back-pressure exerted on the centrifuged liquid before it is projected out of the capsule.
Moreover, other parameters have influences on the quality of the delivered beverage, for example temperature of parts of the machine the beverage is in contact with.
Optimal parameters to apply to prepare a beverage vary greatly according to the type of ingredients to prepare and to the type of beverage to prepare. For instance, ideally, parameters should be set according to coffee powder, strength, aroma, taste, crema, volumes, etc.
WO2010/026053 relates to a controlled beverage production device using centrifugal forces comprising control means for controlling the flow rate, or respectively the pressure, of liquid to match a flow rate reference, or respectively a pressure reference, in a control loop by automatically adjusting the rotational speed of the driving means during the extraction phase of the beverage production depending on the measured flow rate, respectively the measured pressure. The control unit may, for instance, contain set points and values of the rotational speed of the driving means at different phases of the beverage preparation cycle. The capsule to be used can also be associated with a code containing information relative to one or more of the following parameters: flow rates, beverage volumes, speeds, beverage temperatures.
Therefore is a need for being able to provide beverages, (e.g. coffee) having different characteristics of intensity, taste, aroma, foam/crema in a system that is simple and versatile. There is still a need for proposing a new system for which the brewing parameters is better, more precisely, and more independently controlled for improving quality of the delivered coffee and providing an opportunity to deliver a wider range of coffee beverages of different volumes (e.g. 25, 40, 230 ml). There is still a need for proposing a solution to implement a reliable and precise solution for managing all these parameters and their variations, during a brewing process, according to the type of capsule used and the coffee beverages to be produced.
The present invention provides a solution to the before-mentioned problems as well as offers additional benefits to the existing art.